Separated Slurry and the Nitrates Directive

A separator mechanically processes slurry into two fractions, separated liquid and separated fibre. It is important to understand how these fractions are dealt with under the Nitrates Directive Action Programme as there may be significant storage and management implications.

The separated liquid, because of its nutrient content, is classified as slurry under the Nitrates Action Programme and is therefore subject to the spreading closed period.

The separated fibre is classified according to the type of slurry separated.  If the separated fibre is produced from cattle slurry this may be classified as farmyard manure. This contrasts with the separated fibre from pig slurry – which cannot be classified as farmyard manure for the purposes of the Action Programme.

The Nitrates Action Programme will stipulate that farmyard manure will not be subject to the spreading closed period and may be field stored, provided certain practices regarding the location of field heaps are adhered to.

Therefore pig farmers do not gain a storage advantage by separating slurry as 26 weeks capacity must still be provided, in tanks and middens, for the separated liquids and fibre.  Cattle farms must store the separated liquids but, in contrast, can apply or field store the separated fibre thereby reducing the need for storage. They can also take into consideration a reduction in slurry volume, up to a maximum of 20 percent as a result of removing the fibre. This allowance can reduce the volume needed to meet the 22-week storage requirement for cattle and sheep farms.  

If you are considering purchasing a separator be aware of how the Nitrates Directive deals with separated slurry. This could influence your decision.